As far as I'm aware, yes - but if you're in any doubt, best ask the CAA.
I've taken students to France for IR training, and the CAA have never queried it. However, the CAA staff examiners seem reluctant to take IR candidates there, despite my school trying to convince them to do this for 9 months or so (due to cheaper approach fees, easier to book slots, and no further than some UK test routes from our airport). I'm not sure why this is - perhaps there's a doubt about insurance? I know the CAA staff examiners are very conservative when there's any doubt at all about anything.
I believe that doing navigation training in France is the norm for the clubs based in the Channel Islands.
I would question the usefullness of cross-channel navigation as far as the PPL syllabus is concerned, though - the lack of features means it doesn't really contribute much to Ex 18. On the other hand, if a student is going to finish the course in less than minimum hours, and wants to make up the time with a cross-channel checkout (which is useful more from the point of view of seeing the paperwork than the actual flying) then maybe it's a useful exercise?
FFF
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